Communication networks may utilize telephone systems and Internet Protocol (“IP”) based systems to provide communication between computing devices. Session Initiation Protocol (“SIP”) is an application-layer control protocol for establishing, terminating, and modifying multimedia sessions with one or more participants, such as Internet telephone calls, multimedia distribution, and multimedia conferences. SIP communications are typically carried over IP protocols and networks, and permit participants to a SIP session to authenticate the participants, determine each other's location, and agree on a set of media types that can be used for transport of the session.
A “loop condition” or looped SIP communication arises, for example, when a SIP communication is routed from a network which processes the request, and thereafter, the SIP request arrives back at the same network and subsequently the request is processed in an identical manner as the previous processing. Thus, the SIP communication may be routed repeatedly across the same network or domain. If the loop condition is not broken, system resources may be wasted on a SIP communication that cannot be completed. Communication networks are becoming more complex due to the increasing number of terminals that can connect customers and available services. For example, many networks utilize voice peering (e.g., VoIP peering), which refers to the forwarding communications from one internet telephony service provider (“ITSP”) to another. Because communications sent using VoIP peering are not forwarded over the public switched telephone network (“PSTN”) and may be transmitted using particular routing policies, e.g., least cost routing, and because the information of network traversal is not exchanged between service providers, the likelihood of a communication being looped through one or more networks without deterministically and directly associating ingress and egress points may escalate.
Although methods for detecting loop conditions exist (e.g., RFC 3261 describes methods such as a decrementing “Max Forward” counter; and monitoring the lack of change in certain signaling message parameters), it has been observed that known methods are inadequate because increased SIP signaling and instances of malicious attacks are becoming increasingly difficult to control. In addition to detecting loop conditions, there are various other types of undesired SIP communications that a network provider or operator may want to identify and suppress for the purpose of optimizing network resources and efficiency.
Thus, there remains a need for effective approaches to detecting loop conditions, as well as other types of undesired communications, and suppressing the likelihood that looping conditions or other undesirable events may occur on a communication network.